Smartphone technologies (i.e., cellular telephones, such as the iPhone, Android phones, and newer generation Blackberry phones), have provided a new venue for sexual partnering among men who have sex with men (MSM). Indeed, there are a rapidly growing number of smartphone applications designed to facilitate sexual partnering among MSM. Although all smartphones can access Internet sites for sexual partnering, smartphone applications designed for sexual partnering go a step further by utilizing the Global Positioning System (GPS) technology built into smartphones to help MSM identify potential partners who are geographically closest to their current position. As such, these technologies may have accelerated the rate with which men can meet and connect with sexual partners over that of the traditional Internet. Furthermore, given the expediency with which men are able to arrange sexual encounters using these applications, there is cause to question if, when, and how sexual negotiation and serostatus disclosure occurs. The overall study goal is to understand how sexual risk behaviors among MSM may be facilitated by the nature of GPS-enabled smartphone applications, the way they are used, and the process by which sexual partnering occurs via smartphone applications. We will conduct in-depth qualitative interviews with 60 MSM (20 African American, 20 Latino, 20 White; 25% of whom are HIV-positive) who have utilized smartphone applications to meet sexual partners in the past 3 months. For each of the aims below, while our focus is on smartphone use, we will also collect information on their use of Internet partnering sites to use as a context for comparison and identify what might be unique to smartphone usage. The study aims are: 1. Examine how and why smartphone applications are used for sexual partnering, the situations and locations in which they are used, in order to gain insights into how these use patterns might contribute to sexual risk behaviors. 2. Investigate the process by which MSM use smartphone applications to find sexual partners (i.e., who they look for, how they present themselves, how they communicate, extent of safer sex negotiation,and disclosure) to gain insights into how this process may contribute to sexual risk behaviors. 3. Investigate the sexual and emotional states (e.g., more/less urgency, arousal, impulsivity) that MSM experience when seeking or meeting sexual partners using smartphone applications and gain insights into how these states may contribute to sexual risk behaviors. 4. Examine the perceived need and acceptability of a smartphone delivered intervention and assess what MSM perceive as needed components for a smartphone-based sexual risk reduction intervention.